JP2005502297A - Electric motor temperature measuring device and measuring method - Google Patents

Abstract

In order to sense the temperature of the winding area of an electric motor, in particular a linear motor, an additional conductor (30) made of a single conductive material is placed in the winding (20), preferably with iron core teeth (12) and teeth ( It is buried in the section between 12). In particular, the additional conductor is configured as a single insulated double conductor (32) shorted at one end. A change in the resistance value of the additional conductor related to the temperature change is easily detected, so that the temperature of the winding region can be easily estimated. Unlike the above, a measuring element running in the longitudinal direction can be embedded in the winding to detect temperature dependent material properties such as longitudinal expansion and optical properties.

Description

【Technical field】
[0001]
The present invention relates to a temperature measuring device for measuring the temperature of a structural part of an electric motor provided with a winding.
[0002]
When a structural part (primary part) of an electric motor provided with a winding is operated, heat loss is generated that causes the temperature inside the structural part to rise. Excessive temperature rise will damage the insulation of the windings and will also permanently damage its structural parts. Measures must be taken.
[0003]
It is known to mount a thermocouple as a heat sensing means in the winding region for temperature measurement. However, thermocouples are relatively inactive due to insulation reinforcement, and the thermocouple positioning cannot reproduce the optimum state in each measurement, resulting in a measurement error of about ± 10 ° C.
[0004]
Accordingly, an object of the present invention is to provide a temperature measuring device for an electric motor that is easy to apply and gives accurate and reliable measurement results. A further problem is to provide a temperature measurement method.
[0005]
This problem is solved by a temperature measuring device having the features of claim 1 or by the method of claim 15. The dependent claims relate to preferred embodiments of the invention.
[0006]
In the present invention, a measurement element made of a material having a temperature-dependent material property and running over one section along at least one winding is provided, and a change in the material property is detected using a detection device.
[0007]
Therefore, the measuring element is, for example, a rod, and the temperature-dependent length change is measured with an appropriate length measuring instrument at one or both ends of the rod. Basically, detection can also be done by optical length measurement.
[0008]
Furthermore, the optical properties of temperature-dependent glass or plastic may be evaluated. In this case, the measuring element can be a glass or plastic fiber, for example an optical fiber.
[0009]
The measuring element may be composed of a single conductive material in the section region.
[0010]
According to the invention, since the measuring element runs over at least one winding section, the material of the measuring element is heated in that section, and the temperature-dependent material properties change accordingly, and the temperature You can reverse guess.
[0011]
In the present invention, an additional conductor made of a uniform conductive material can be used as a measurement element. The additional conductor runs through the section along at least one winding, and its end is led out of the motor. The invention then takes advantage of the fact that the electrical properties, in particular the temperature dependence of the known material resistance, are usually known or easily measurable. According to the present invention, since the additional conductor runs through at least one winding section, the material of the additional conductor is heated in the section, the resistance changes accordingly, and the temperature is inferred from the resistance change. can do.
[0012]
This effect can also be used in the method of the present invention in which the direct current resistance value of at least one coil or winding is monitored during operation and the temperature is estimated backward from the resistance value.
[0013]
In the device according to the invention, a measuring element or an additional conductor is mounted on the winding or preferably embedded in the winding in order to detect the temperature in the winding.
[0014]
The additional conductor may be configured as a single insulated conductor.
[0015]
Usually, the highest temperature occurs in the winding region in the iron core, so that the section of the measuring element is likewise arranged in that region. In particular, the section is arranged to cover the entire area of the winding inside the iron core. At that time, the section can be divided into a plurality of partial sections.
[0016]
In order to increase the length of the additional conductor for measuring the resistance change, the additional conductor can be an insulated double conductor having a short-circuited end. The additional conductor may be wound as a coil in the winding region.
[0017]
If the diameter of the measuring element is substantially the same as the diameter of the electric wire forming the winding, the winding structure can be simplified in particular.
[0018]
The temperature measuring apparatus and method according to the present invention can be applied to both rotary electric motors and linear motors.
[0019]
Embodiments of the present invention will be described with reference to the accompanying drawings.
[0020]
FIG. 1 shows a primary part of a linear motor, which basically has a structure similar to the conventional one having an iron core 10 having teeth 12 for winding, and a winding 20 is mounted on the teeth 12. Other structural parts of the linear linear motor primary part are well known, and further description thereof is omitted here.
[0021]
In addition to the structural part described above, the primary part according to the invention comprises at least one additional conductor 30 with a section embedded in at least one winding. In the case shown, the additional conductor 30 is insulated and includes two partial sections 32 and 36 in the form of a double conductor. This double conductor is short-circuited at one end 34. The partial sections 32 and 36 are embedded in the coil so as to cover almost the entire region of the winding 20 from the coil between the teeth 12. The partial sections 32 and 36 are connected to each other via a crossover 38. The connection end of the additional conductor 30 is led out from the primary part, and is connected to an electric circuit necessary for resistance measurement outside.
[0022]
FIG. 1 shows three additional conductors 30 belonging to each winding 20. These three additional conductors can be individually measured for each phase U, V, and W during operation with a three-phase alternating current by separately using them to measure the temperatures of the individual windings.
[0023]
The electrical resistance of the additional conductor 30 is generally measured by an appropriate method not described in detail, and the resistance value is calculated from material properties depending on the size and temperature of the conductor or detected by calibration of the additional conductor. Compare with the resistance value.
[0024]
As the material for the additional conductor, any conductive material having an appropriate temperature dependency can be used. The individual conductors of the additional conductors must be formed from a “single” material, for example a unitary material, at least in the section region of the winding. As a result, it is possible to avoid the resistance effect generated at the contact point between the materials and simplify the detection of the original resistance value.
[0025]
It is also possible in principle to use the coil or winding 20 itself for temperature detection. Again, since the material properties are temperature dependent, the temperature can be estimated by measuring the quantity of electricity related to resistance or resistance change. This type of measurement can be performed, for example, under a single coil, or with all the coils belonging to one phase, by appropriate calibration of the primary part, for example by calibration of the resistance value depending on the adjusted temperature. it can. Also, a conversion table for detecting the resistance value, that is, detecting the temperature value can be prepared.
[Brief description of the drawings]
[0026]
FIG. 1 is a view of a primary portion of a linear motor as viewed from an end surface side.
FIG. 2 is a plan view in which a part of the primary part of FIG. 1 is broken.
[Explanation of symbols]
[0027]
10 Iron core, 12 teeth, 20 windings, 30 Additional conductor, 32, 36 Partial section, 34 One end of double conductor, 38 Crossover

Claims (16)

In a temperature measuring device for measuring the temperature of a structural part of an electric motor provided with a winding (20),
A device comprising a longitudinal measuring element made of a material having a temperature dependent material property and running over a section along at least one winding and a detection device for detecting a change in the material property. 2. The device according to claim 1, wherein the measuring element is a rod and the material property is the longitudinal expansion of the rod. 3. A device according to claim 1, wherein the material is glass or plastic. 4. A device according to claim 1, wherein the detection device senses the optical material properties of the material. The measuring element is an additional conductor (30) made of a single conductive material, which runs over a section along at least one winding (20) and whose termination is led out of the motor. The apparatus of claim 1 characterized in that: Device according to one of the preceding claims, characterized in that the measuring element (30) is mounted on the winding (20). Device according to one of the preceding claims, characterized in that the measuring element (30) is embedded in the winding (20). Device according to one of the preceding claims, characterized in that the additional conductor (30) is an insulated single wire. 9. A device according to claim 1, wherein the section is in the region of the wound iron core. 6. A device according to claim 1, wherein the measuring element in the section is a double conductor short-circuited on one side. 11. A device according to claim 1, wherein the section comprises a plurality of subsections covering substantially the entire area of the winding inside the iron core. 12. A device according to claim 1, wherein the diameter of the measuring element corresponds to the diameter of the wire of the winding. Device according to one of the preceding claims, characterized in that the section extends to wrap around the teeth (12) of the iron core. A linear motor or a rotary electric motor comprising the temperature measuring device according to claim 1. A method for measuring the temperature of a winding region of an electric motor, comprising: monitoring an electrical characteristic of at least one coil during operation of the motor; detecting an instantaneous resistance of the coil; and detecting a temperature in the winding region from the coil resistance. . The method of claim 15, wherein a plurality of coils are monitored.